Re: Gear Boxes
 

Yep. That would work fine.

Re: Gear Boxes
 

Just to clarify, the bearing block is the 1/4" piece on the front of the gearbox. So, the axle is still cantilevered, but the design doesn't rely on the gearbox's internal bearings to keep the shaft aligned.

Still probably fine?

Re: Gear Boxes
 

It will help some, but putting that bearing block on the other side of the wheel will be much better (assuming you have chassis there to put it on)

Re: Gear Boxes
 

It looks like you've got two hubs installed there. Typically one is sufficient.

Re: Gear Boxes
 

I see we're not the only ones considering using the 545s to drive the bot.

We were thinking of running them through the 3.67:1 AM planet (its more reliable than the BB ones) and then use a 60:12 chain reduction.

It seems kind of crazy using such a small motor, but considering how little torque is necessary it kind of works out...

Re: Gear Boxes
 

If we were to direct drive the wheels from a banebots gearbox using the 545's what sort of reduction would we be best to go with?

Re: Gear Boxes
 

Hachiban's planned gearing will be about 18:1 and it will get them somewhere around 10 feet per second robot speed, which is pretty typical.

So, if you can find a 16:1 gearbox, that should get you pretty close to where you want to be.

You might want to do some calculations about the torque you'll have available at that reduction, and maybe see if you can figure out your maximum acceleration, and whether or not you'll be able to spin the wheels at take off.

Re: Gear Boxes
 

Okay thanks we will do all the math when it gets closer to our build season. (in June sometime)

Re: Gear Boxes
 

Has anyone calculated the CoF of those wheels on the carpet, to see if these motors/gearbox setups will stall those smaller motors?

Re: Gear Boxes
 

Stall torque claimed for the motors with a 16:1 planetary gearbox (Banebots web page) is 592 oz-in, or 3.0 lbs-ft. Looks like it'll be close on FRP and probably stall on carpet, eh?

Re: Gear Boxes
 

Yeah, we went back and double checked the math, and with that reduction the motors would have been drawing too many amps. (19 A is okey for a CIM but NOT for a tiny 545!)

We're currently looking at a 2 CIM drive geared to around 19 fps. This may sound like a stupidly high number, but with this setup we won't be producing as much torque and therefore won't be spinning the wheels as much.

We've tried it out on the proto and acceleration was improved a great deal.

Of course every drive train we've ever built has sucked... so bear with me:rolleyes:

Re: Gear Boxes
 

just make up for it with one of your typical incredible ball handling thingys!

Re: Gear Boxes
 

This is why we're going with a 64:1 reduction on the 545's for our drivetrain. At 100% efficiency this slips the wheels on a full weight robot at only 1/4 of the max torque, which is more than enough safety margin to keep the Banebots running cool and fine on FRP. Carpet will be closer to the limit but still under it I believe, and the amount of driving being done on carpet should be little enough to avoid problems.

Also, it seems like a 16:1 would be much to high of a wheel speed to be useful. Unless my math is horribly off, the Banebots site specs No load RPM at 988, and with a 6" wheel this gives a theoretical top speed of 25 fps!